Numerous lock constructions have been developed and are widely employed by individuals to prevent unauthorized persons from gaining access to any area which has been closed and locked. Although many locks are constructed to be opened by a key, numerous combination locks have been developed which are opened by knowledge of a particular combination.
One particular type of combination lock that has become very popular, due to its ease and convenience of use, is a combination lock which employs a plurality of rotatable independent dials, each of which comprises a plurality of indicia, usually numbers or letters, which define the combination for releasing the lock. Although locks of this general nature had been available for several decades, these prior art combination lock constructions are typically employed in low security areas, due to their inability to resist forced entries in which excessive force is applied to the lock.
In those areas wherein a high security lock system is required, prior art constructions have relied upon padlocks which require a key for operating the lock between its alternate open position and closed position. Due to the ease with which keys are often lost or misplaced, as well as the proliferation of the keys required for many individuals to carry, high security padlocks requiring keys for operation have become increasingly unpopular. However, prior art constructions have been incapable of providing a high security padlock incorporating a combination system for operating the padlock, either independently or in combination with a key.
The present invention provides a combination padlock for effective operation in high security operations. The combination padlock has a lock body constructed as a single piece to enhance the durability of the padlock in tensile test and impact test.